In October, 2004, Harvard graduate student Alexander Pring-Wilson was found guilty of voluntary manslaughter in connection with the killing of 18 year-old Cambridge hotel clerk Michael Colono. An altercation began between the two men outside a pizza parlor and ended with Pring-Wilson stabbing Colono 5 times in 70 seconds. Pring-Wilson claimed at trial that he was acting in self-defense, but the court refused to allow him to admit evidence of past acts of violence by Colono, including incidents where (1) he was arrested after throwing money in the face of a pizzeria cashier and shattering glass in the pizzeria's front window, and (2) he allegedly assaulted two people on a subway and spit in the faces of his arresting officers.

Soon after his conviction, however, the Massachusetts Supreme Judicial Court made an odd evidentiary decision, which changed its already odd evidentiary "rules" and led to Pring-Wilson being granted a new trial. In Commonwealeth v. Adjutant, 824 N.E.2d 1 (Mass. 2005), the court adopted a "new common-law rule of evidence" that in cases where a defendant is claiming that his attack on the "victim" was self-defense and is not claiming to have any knowledge of the "victim's" allegedly violent past or reputation, evidence of the "victim's" reputation for being violent is inadmissible while evidence of specific past acts of violence by the "victim" are admissible in the discretion of the judge. The court came to this conclusion as "a matter of common-law principle," despite acknowledging the fact that most courts, including all federal courts pursuant to Federal Rule of Evidence 405, hold the exact opposite: in self-defense cases, evidence of the "victim's" reputation is admissible while evidence of specific past acts of violence by the "victim" are inadmissible.

Now, the reason that Massachusetts had to adopt this "new common-law rule of evidence" is because it does not have an officially adopted code of evidence. Instead, Massachusetts evidence law derives from a mishmash of common law, statutes, procedural rules, federal and state constitutions, the Federal Rules of Evidence, and the Massachusetts Proposed Rules of Evidence (which were never adopted). See Jeffrey S. Siegel, Note, Timing Isn't Everything, 79 B.U. L. Rev. 1241, 1244 (1999). Understandably, this "tapas" approach to creating rules of evidence creates anomalous and frankly bizarre results such as the Adjutant court's "new common-law rule."

The question now becomes whether Pring-Wilson's ability to present evidence of past acts of violence by Colono will change the result in his new trial. Harvard law professors asked about the case have noted that the new evidence will certainly provide an obstacle to the prosecution while remaining uncertain about whether the evidence will result in Pring-Wilson being acquitted this time around.